[werk_ag]

The relay transmit antenna is mounted only a few inches from the main receive antenna so the receive antenna is getting the RF from TX0, TX1 and the relay transmitter. With a transmit antenna only a few inches away from a receive antenna that's a hostile RF environment.

Just my too cents on this:

When the Pro2 PLUS relay a signal, the receiver is disabled, or by other words it is not listen for any incoming signal. So having the two antennas close to each other should not be a problem.

Turning off the relay function recovered some RF efficiency from TX0, so there has to be some interaction/interference. Separating the antennas recovered even more RF efficiency from TX0.

This may happen, but perhaps by other reasons. Everything we do takes time to execute, disabling the relay function, allows the main receiver to be a little more time listening for incoming signals.

And if you watch closely you can see when there are transmissions from TX1 and TX0 that the relay transmitter does not transmit. I'm guessing that means the receiver didn't receive either TX1 or TX0 at that specific point in time. Does that make sense?

Yes, makes sense. The relay only transmits, after it receives a valid data packet from any of the TX units.

There is also another thing I don't clearly understood... You have referred somewhere that you had changed a transmitter module because its frequency its on top of the other TX unit. My understand on this, is that the best situation is exactly when all the transmitters are transmitting in a frequency very close or top of each other. Collision will ever happen, no matter if the frequency of each transmitter is on top or not. One thing already observed is that the receiver will get more datapackets when the frequency of each TX is closer to each other.

Currently I think I should never had implemented that thing, I call "RF Efficiency", mainly because its usefulness, it's to be seen in a completely different way, than it is seen.
Trying to get 100% or 90% "RF Efficiency" is like searching for the "Holly Graal"
And yes, the more TX units, the less the "RF Efficiency" shown for each one. The idea is reach a good balance between them, having two or three at 90% its almost impossible. Having two units, each other running at around 60 to 70% ensures a reliable operation of the whole system.

Another little bit... perhaps it helps to look for the problem from another point of view. Some times the problem is not having a week signal, is having a too strong signal. Those modules are able to give an output of around 25mW, think of it. Recently one of our Test / Developers (meteoestarreja) as managed to receive a signal from one of these modules, 2Km away (open field) from the transmitter.

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